Tunnel boring machine



July 23, 1946. H. o. THOMPSON TUNNEL BORING MACHINE Filed Oct. '7, 1944 3 Sheets-Sheet 1 IN VEN TOR, HOWARD 0. THOMPSON 4 fl AT TORNEK July 23, 194-6, H. o. THOMPSON 2,404,605

TUNNEL BORING MACHINE Filed Oct. 7, 1944 5 Sheets-Shet 2 INVENTOR; v

HOWARD 0. THOMPSON ATTORNEY.

July 23, 1946. H. o. THOMPSON TUNNEL BORING MACHINE f Filed Oct. '1, 1944 s Sheets-Sheet 3 IN ENToR; HOWARD a. THOMPSON.

Patented July 23, 1946 UNITED STATES PATENT OFFICE TUNNEL BORING lliACHINE Howard 0. Thompson, San Francisco, Calif.

Application October 7, 1944, Serial No. 557,662

. 8 Claims. 1

The present invention relates to improvements in tunnel boring machines, and its principal object is to provide a machine of the character described that will bore the full area of the tunnel in one operation. 7 p

For the purposes of my invention it is proposed to use a compound drilling arrangement, in which a, pairof drill bits mounted alongside of one another are made to rotate about their own axes and are also made to revolve about an intermediate axis, thus drilling a cylindrical tunnel of twice the drill bit diameter and of four times the drill bit area.

It is further proposed to mount this drill bit arrangement on a vehicle which is provided with means for anchoring the same against the tunnel Wall and also with means for advancing the drill bit arrangement toward the tunnel wall under steady pressure for feeding the drill bits.

It is further proposedto provide a vehicle which may be readily advanced from time to time, as the drill bits reach the end of their active travel so that a complete tunnel maybe bored by successive alternate drilling operations and advances of the vehicle.

A further object of my invention is to provide a suitable driving arrangement whereby the compound movement of the drill bits about their own axes and about an intermediate axis may be effected by the single drive selected of relatively simple character.

And finally, I propose to provide a special type of drill bit particularly designed to cooperate with its companion in drilling the entire area and in throwing the cut material outward.

Further objects and advantages of my tunnel boring machine will appear as the specification proceeds, and the novel features of the same will be fully defined in the claims hereto appended.

The preferred form of my invention is illustrated in the accompanying drawings, in which:

Figure 1 shows a front view of my tunnel boring machine;

Figure 2, a longitudinal section taken along line 2--2 of Figure 1;

Figure 3, a cross-section taken along line 3-3 of Figure 2, looking in a forward direction;

Figure 4, a cross-section taken along line 44 of Figure 2, looking in a rearward direction; and

Figur 5, a sectional detail view taken along line 55 of Figure 2.

While I have shown only the preferred form of my invention, I wishto have it understood, that various changes or modifications may be made Within the scope of the claims hereto attached without departing from the spirit of the 5 carried by the disc and gearing between the cutters and the housing. I

The vehicle I may be of any suitable type, and preferably comprises a bed plate I and one or more pairs of wheels 8 supporting the bed plate through suitable links 9 which allow the wheels to be retracted, as shown in the dotted line position, and to be placed'in any suitable working position, depending upon the size of the tunnel to be bored. Suitable means (not shown) may be used for adjusting the links and for locking the same in adjusted position.

The vehicle is preferably provided'with a suitable number of stingers In which may be driven into the wall of the tunnel for holding the vehicle in place. Any suitable means (not shown) may be used for driving and for retracting the Stingers, and, in fact, any other suitable means may be used for holding the vehicle in position during drilling operations.

The housing 2 is mounted on the bed plate of the vehicle with freedom of endwise motion and is guided in any suitable manner as by rails ll projecting into slots l2 in the'bed plate.

The housing is made essentially in the form of a sleeve l3 having a cylindrical inner face [4 and an angular outer face l5. The forward end of the sleeve is guided by the similarly shaped bearing [6, whilethe rear end of the sleeve terminates in an enlargement ll carrying the rails The enlargement in the rear of the housing and the bearing 16 for the front of the housing are dimensioned to support the'housing in spaced and parallel relation to the bed plate, and are constructed to hold-the housing against rotary motion while, allowing of endwise movement. The front end of the housing projects beyond the bed plate and carries the gear wheel l8;

The shaft 3 extends clear through the housing 2 and is supported therein in suitable bearings l9. The rear end of the shaft is preferably supported in an additional bearing 20 mounted on the bed plate.

The shaft is revolvablein the housing and is held against endwise movement therein by a collar 2| on the shaft riding in an annular recess 22 in the enlargement of the housing. It is rotated by means of gearing 23-24 connecting it to the motor 25 carried by the housing.

' The front end of the shaft 3 projects beyond the housing 2 and carries the plate 4, which may be splined thereto as at 26. The plate has two stub shafts 21 mounted therein at diametrically opposed points and with freedom of rotary movement, and these shafts carry the drill bits or cutters 5.

The drill bits are of specific construction.

Their outer edges are scalloped or waved so as to present alternate crests 28 and depressions 29 and they are dimensioned for meshing at the centerline, with a relatively loose fit so as to be adapted for accommodating a certain amount of dirt and loose material between the same.

Each of the bits has as many cutting edges 30 as it has crests in its periphery and each cutting edge runs from the center of the bit to the center of the crest in the periphery. It is curved in the direction of rotation so as to fling the separated material outward through centrifugal force. The cutting edges, which are made of specially hardened material, descend into depressions,

R which are generally indicated at 3|, and are adapted to carry the dirt outward. The lowest lines of the depressions run from the center of the bit substantially to the centers of the depressions in the wave of the periphery.

It should be noted that the cutting edges may be made removable, in the form f blades embedded in the bit material.

Dueto this construction, it will be noted that the cutting edges, reachin clear to the outer portions of the crests 28, overlap at the centerline and are sure to,cut away 'all the material from the central area of the tunnel face being worked on, when the bits are rotated.

.The two drill bits revolve about the center of the main shaft due to their mounting in the plate 4. At the same time they revolve about their own axes through the gear trains 6 connecting the same to the gear I8 on the housing.

The gear trains 6 include the gear wheels 32 on the stub shafts 2'! and idlers 33 interposed between the same and the gear l8.

It will be noted that I provide one idler for one of the drill bits and two for the other. This has been done to cause rotation of the drill bits in opposite directions without changing their relative distances from the axis of theshaft 3, which distancesshould be alike for proper balancing,

The housing 2 with the main shaft 3 and the drill bit arrangement may be advanced on the vehicle toward the face of the tunnel by any suitable means exerting steady forward pressure, as by a plunger 35 (see Figure bearing on a flan e 36 whichlatter rides in a central slot 31 in the bed plate 1. The plunger may be driven by hydraulic pressure through the pump'38 driven by a motor'39 and subject to a control indicated schematically at 40.

The operation of my machine is as follows: The vehicle I is first firmly anchored against The motor gearing 6. Thus the drill bits cut into the tunnelwall'in acompound movement, cutting and 4 revolving at the same time so as to cover the entire face of tunnel and an area four times the size of the individual drill bits.

With the motor 39 started, the plunger 35 exerts steady forward pressure against the tunnel wall and feeds the drilling apparatus forward until the latter has reached the end of its forward travel, which is controlled by the length of the slots I2. When this point has been reached, the motors are stopped, the anchoring means are disconnected and the vehicle is pushed forward by any suitable means, as by a tractor, and is re anchored for renewed operation of the'drilling apparatus.

Thus the drilling operation is continued by successive alternate drillin and advancing of the vehicle to provide a tunnel of uniform diameter.

I claim:

1. In a tunnel boring machine, a main drive shaft, a pair of revolvable drill bits offset with respect to the shaft, means for rotating the drill bits on their own axes and means for revolving the drill bits about the axis of the main shaft, the drill bits being substantially in contact with one another so as to drill the entire circular area defined by their combined diameter and having peripheral edges formed with shallow waves intermeshing with one another for crushing the material therebetween. V

2. In a tunnel boring machine, a main drive shaft, a pair of revolvable drillbits offset with respect to the shaft, and a driving connection between the'shaft and the bits whereby thelatter are rotated on their own axes/and are revolved about the axis of the. main shaft the drill bits having cuttingedges in the faces thereof curved are rotated in opposite directions about their own axes and are revolved about the aXis of the main shaft, the bits having waved circumferential surfaces meshing with one another.

4. In a tunnel boring machine, a bed plate, a housing slidable thereon, a shaft revolvable in the housing, means for holding the shaft against endwise movement in the housing, a disc attached to the shaft, a pair of drill bits revolvably mounted in the disc, means for revolving the shaft whereby the drill bits are revolved about the axis of the shaft, a gear on the housing, and gearing between the latter gear and the drill bits'for rotating the latter about their own axes in opposite directions, the bits having waved circumferential surfaces meshing with one another.

5. In a tunnel boring machine, a vehicle bed having a bearing in its front end and a. bearing in its rear end, a carriage supporting the bed in horizontal position, a sleeve housing-non-revolw' ably and slidably mounted in the front bearing and having a motor mounted thereon, cooperative guide members on the sleeve and the bed, a shaft revolvable in the housin and supported in the rear bearing, meansfor holding the shaft against endwise movement in the housing, a driving connection between the motor and the shaft for rotating the latter, a disc mounted on the front end of the shaft, a pair of cutters carried by the disc, cooperative means on the cutters and the housing for rotating the cutters in opposite directions, and fluid pressure means bearing on the housing for exertin forward pressure on the same.

6. In a tunnel boring machine, a vehicle bed having a housing non-rotatably mounted thereon, a shaft revolvable in the housing and extending beyond the same, a gear wheel on the housing, and a drill head mounted on the shaft adjacent the gear wheel, the drill head comprising a disc fixed to the shaft, a pair of cutters revolvably mounted upon the front of the disc, and gearing mounted upon the rear of the disc and cooperating with the gear wheel in revolving the cutters in opposite directions when the shaft is revolved, and the drill head forming a unitary structure operable for attachment and removal as a unit.

7. In a tunnel boring machine, a vehicle bed having a bearing thereon, a sleeve housing having one end slidably and non-revolvably supported in the bearing and having an enlargement at operable with the gear wheel for revolving the drill bits in opposite directions.

8. In a tunnel boring machine, a vehicle bed havin a bearing thereon, a sleeve housing having one end slidably and non-revolvahly supported in the bearing and having an enlargement at the other end with a flat face riding on the vehicle bed, a shaft revolvable in the housing and held against endwise movement therein, a gear wheel on the housing, and a drill head on V the shaft having a pair of drill bits and means HOWARD O. THOMPSON. 

